module.exports = function uuidv4() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
    const r = Math.random() * 16 | 0, v = c === 'x' ? r : ((r & 0x3) | 0x8)
    return v.toString(16)
  })
}
